Comments on: Armature Upgrade and More Trials https://prometheusfusionperfection.com/2012/07/24/armature-upgrade-and-more-trials/
Developing Clean, Cheap, Open Source Energy with the Bussard Reactor.Tue, 14 Aug 2012 18:42:31 +0000
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By: Inconclusive Symmetry Test « Prometheus Fusion Perfection https://prometheusfusionperfection.com/2012/07/24/armature-upgrade-and-more-trials/#comment-3417
Tue, 14 Aug 2012 18:42:31 +0000http://prometheusfusionperfection.com/?p=3409#comment-3417[…] as expected, despite the unusually high pressure. This is good, but also strange in light of the last test results, in which the charge at charge at the center of the core became less negative when we fired the […]
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By: crossedfields https://prometheusfusionperfection.com/2012/07/24/armature-upgrade-and-more-trials/#comment-3350
Fri, 03 Aug 2012 20:10:20 +0000http://prometheusfusionperfection.com/?p=3409#comment-3350You’re trying to use a Langmuir probe in a magnetised plasma … Very tricky physics there. It could mean anything!
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By: Symmetry Test « Prometheus Fusion Perfection https://prometheusfusionperfection.com/2012/07/24/armature-upgrade-and-more-trials/#comment-3318
Sat, 28 Jul 2012 00:29:55 +0000http://prometheusfusionperfection.com/?p=3409#comment-3318[…] more pressing issue is measurement. In light of last week’s murky trial results, It’s apparent that a single langmuir probe in the center of our Polywell does not […]
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By: erblo https://prometheusfusionperfection.com/2012/07/24/armature-upgrade-and-more-trials/#comment-3304
Wed, 25 Jul 2012 22:38:55 +0000http://prometheusfusionperfection.com/?p=3409#comment-3304I’m not an expert but I think it’s important to consider that in your setup the electron beam should hit the Langmuir probe while the Sydney experiment (and your previous attempt?) had it aimed at an angle away from the probe. This means that the zero reading corresponding to no confinement is the full potential of the beam (-50V) instead of ~0V. The maximum field resulting in -25V then means:

– The full interior of the device is now at a negative potential due to trapped electrons. The trapping is effective enough to result in a central negative cathode at half the beam potential. :)
Beam: -50V -> 0V, Cathode: 0V -> -25V

Or:

– The magnetic field deflects/disperses/interferes with the beam so that only enough hit the probe to give a reading of -25V instead of -50V, unfortunately telling us very little about the confinement. :(
Beam: -50V -> -25V, Cathode: 0V -> 0V

Or a combination thereof.

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By: Remy Dyer https://prometheusfusionperfection.com/2012/07/24/armature-upgrade-and-more-trials/#comment-3298
Wed, 25 Jul 2012 07:13:44 +0000http://prometheusfusionperfection.com/?p=3409#comment-3298Actually, on second thoughts, you could just try moving the anode up into the nearest coil.

This would do nearly the same thing, in terms of keeping force on the electron beam until it’s through the tightest part of the magnetic flux. (which would be close to the center of the that nearest coil.) This should stop the Langmuir probe going “more positive” when the coils fire. (What exactly it’ll do I have no idea, I hope go more negative again.)

It should be just entirely within the magrid there. But cut a slot along the anode tube though, so it doesn’t accidentally form a one-turn winding in the middle of your coil! (probably a good idea anyway, I think)

But having the anode “cage” about the whole magrid would be much better – this way any electrons leaking out through the cusps would be encouraged to leak back in almost immediately, and being outside the magnetic field, the electrons won’t be able to hit the anode and leave so easily, allowing for multiple pass trajectories.

I think what may be happening is that the coils are deflecting about half the electron before they enter the coil. So the Langmuir probe voltage isn’t really “positive”, really just “not as negative as it was without the magnetic field”.

My next suggestion would be to wind a fine wire loosely and “toroidally” about each of the coil holders, (as if the coil holders were a toroid transformer core, this new winding will be everywhere perpendicular to the main coil windings, and so shouldn’t cop any current from the magnetic field, because it will run “with” the field and not across it.)

I guess you could instead make a spherical shell anode to go around the magrid to the same effect – just punch out holes for each of the cusp lines – on each face and in each corner. Would really look like a “wiffleball” then!
Could be in several parts, and gaps are ok.

Then wire each of these “cage electrodes” together – and use them all as the high positive voltage anode. They need not actually form a circuit, or even each be connected at both ends, just use them as a loose cage insulated from the coils, so you can keep running the coils separately, yet still make the whole magrid assembly into, well, a grid.

This way it won’t matter if the external part of the magnetic field deflects the electrons – they’ll still be pulled inwards if they’re anywhere outside the Magrid. Don’t need to worry much about “focusing” the beam either, since this will do that anyway. So long as the electron source has line of sight on the centre of the grid it’ll work.

But once those electrons get inside, then they won’t see the anode electric field at all. Because of Faraday shielding they’ll see just each other, and on their way out, the inside-facing magnetic field…

You might need a couple of Langmuir probes to see the shape of the potential well, rather than just one in the middle. All the interesting physics happens close to the inside edge of the WB, just within the magrid’s ID and near to the coils. To get the WB mode to light off, you’ll probably need a lot of electron gun drive current to get the electron number density up high enough that Lenz’s Law en masse starts to counter the magnetic field within the magrid.

You could then use the existing anode near the filament as a “grid” connection to control the current from the filament – a sense resistor in the earth connection i suggested there will let you measure what the electron beam current is.

PS: I’m perfectly happy to get no credit: Just seeing your next post is reward enough! Still, it was nice, thanks! But you needn’t again ;)